THE ENVIRONMENT Fresh visit to the Great Barrier Reef in its death throes

by Dr Walter Starck

News Weekly, November 2, 2019

Several decades ago, academic researchers found that threats to the Great Barrier Reef (GBR) attract media attention, generous funding for research, and public recognition for themselves. Eco-threats began to eclipse basic research in funding and research interest.

Today, we have a whole generation of researchers whose entire experience of the GBR has been in the context of finding, investigating and promoting environmental “threats” and they tend to perceive every fluctuation of nature as evidence of them.

Reefs are highly dynamic and variable communities. Large differences are common between nearby reefs and on the same reefs from year to year. Occasional devastation and recovery from storms, floods, bleaching, upwelling and starfish plagues are not uncommon. Even just a good rain during an especially low tide can be devastating to exposed corals. Almost every year tropical cyclones cross the reefs, leaving trails of thousands of hectares of broken coral plus a heavy blanket of silt from the ground-up coral and stirred-up sediments.

The most easily accessible coastal reefs are especially subject to natural extremes of temperature, floods and storms that result in extensive coral mortality. The huge geographic area of the GBR means that damaged areas can always be found somewhere. For those with limited direct experience of reefs and primed by belief in a litany of hypothetical threats, every fluctuation of nature provides evidence that appears to confirm their hypotheses.

Another factor in the growing detachment of environmental science from empirical reality has been the rise of computer modelling. This can be done comfortably in office hours, presents an aura of advanced expertise and certainty, can be “adjusted” to give desired results, and is inaccessible to independent examination.

Although computer modelling can be a powerful tool for analysis and prediction, this is true only where good input data are available, dynamics are well understood, and models are mathematically verified and empirically validated. None of this is true of environment modelling and the results are only the modeller’s opinion of a possibility.

In regard to GBR water quality and runoff, the following, from a 2006 study by Professor Robert Carter, remains true: “the claim of human-related nut­rient enrichment in the Tully River, and regionally, is without substance. No detectable trends in GBR water quality have occurred since systematic measurements were first started in the 1980s.”

There is no actual evidence of decline in water quality and no reason to expect any. In fact, the opposite is true. The use of fertiliser and agrichemicals in the GBR catchment has decreased over recent decades. Traces of pesticides at their highest are well below any levels known to be harmful. Nutrient runoff to the reef is orders of magnitude less than natural fluctuations caused by internal waves from the open ocean and that are considered to be beneficial.

As for sediment, the inshore waters are blanketed by a natural accumulation of thousands of years of wet-season runoff from an ancient dusty landmass. This is kept suspended much of the time by wave action on a windy coast. The idea of increased sedimentation since European settlement is entirely speculative.

In contrast, it is easily observed that wet-season runoff from cropland and improved pasturage is usually clearer than runoff from either rainforest or other natural vegetation, both of which provide less groundcover. If anything, there may well be less sediment runoff now than there was before European settlement.

In any event, the corals on nearshore reefs are species adapted to turbid conditions and their frequent mortality from runoff is entirely due to fresh water, not to sediment, nutrients or agrichemicals.

Currently there is a plan greatly to increase the environmental demands and restrictions on primary producers in the GBR catchment. This is claimed to be necessary to deal with declining water quality and dying reefs. A key element in the campaign for increased environmental regulations, and funding to “save the reef”, has been photos of exposed reefs at low tide near Bowen, which are said to have been killed by the effects of climate change and declining water quality.

What give these images special impact are comparison images in the book by William Saville-Kent, The Great Barrier Reef of Australia: Its Products and Potentialities, published in 1893, which are said to be in the same location. However, the exact location of the early photos and the tide level at the time they were taken are unknown. It should also be noted that a flood event stemming from a cyclone in 1918 is reported to have killed all the corals in this area; that is to say, 25 years after Saville-Kent took his photos.

A survey in 2012 found that dating of the dead corals sampled near the assumed locations of the historical photographs coincided with major flood events in 1970, 1990–91 and 2008. Although various uncertainties were mentioned in attributing the cause for an apparent low level of coral recovery in these areas, this has been ignored in favour of the dramatic photo comparisons, which have been presented as proof of the reef dying from climate change and pollution.

In August this year, Professor Peter Ridd and I were invited by Dr Jennifer Marohasy of the Institute of Public Affairs to offer our assessment of this area.

The 2012 survey site at Stone Island was located near the middle of an extensive reef flat several hundred metres wide, extending from the southern side of the island.

This is what the area of the 2012 survey looks like. Gloucestor Island can be seen in the background.

However, only about 30 metres further out along the edge of the exposed reef flat, we found there was a healthy fringing reef stretching for nearly two kilometres. As this area is exposed to the prevailing strong southeasterly winds of this area of coast, breaking waves on the reef edge and turbidity limit access much of the time. We were fortunate to have several hours of calm on two days while we were there.

Fringing reef with luxuriant coral along the southeast end of Stone Island.Gloucester Island and Cape Gloucester can be seen at top.

Just around the southeast corner of the island, a 1.5-kilometre-wide bay fronts its eastern side. The water here is deeper and clearer. A broad band of diverse and luxuriant corals stretches across the entire bay. Over much of this area coral coverage is near 100 per cent, as depicted here.

The second location of the 2012 survey was along the southern side of the bay known as Port Denison, where Bowen is located. Here, there is a kilometre-wide shelf of coastal sand and mudflats. For a couple of kilometres, the outer edge of this shelf supports a fringing reef known as Bramston Reef. The conditions here are less favourable for corals and they are much less diverse and luxuriant in their development than at Stone Island.

The 2012 survey reported mostly dead corals with little signs of recovery. We found numerous healthy heads of star corals not unlike the 19th-century photos but without the plate corals that were also present in those pictures. There were, however, scattered dead plate corals, the condition of which indicated a recent period of recovery followed by another die-off. These more delicate species are particularly susceptible to die-offs in such a marginal habitat.

Just offshore from the outer edge of the fringing reef, there is also a number of large healthy coral bommies, attesting to the ongoing long-term survival of a few species adapted to the rough turbid conditions of this location.

Multiple large colonies of living favites corals along the outer edge of Bramston Reef, with Gloucester Island in the background.

Several key things are apparent from what we found.

One is that the extensive areas of healthy and even luxuriant coastal reefs we found around Stone Island clearly refute any claims of declining water quality or climate change being responsible for dead corals on exposed reef flats where die-offs are common. Water quality and climate change would not affect corals in one place and leave extensive areas of diverse healthy reef immediately next to it.

The lack of any mention in the 2012 survey of the abundant healthy corals nearby poses the question: were the surveyors unaware of them, or were they just ignored; and, in either case, why?

Establishment of government policy in response to activist campaigns and media accounts of research claims with no critical assessment of the underlying research amounts to malfeasance and needs to be recognised as such.

Meanwhile, despite all of the purported threats, the GBR remains a healthy, vibrant natural community, as can be attested by the thousands of visitors who enjoy its beauty every day. However, in addition to the hundreds of millions of dollars spent in devising hypothetical solutions to imaginary problems on the reef, almost every productive economic activity in the region is being increasingly impacted by regulations and res­trictions said to be necessary to save the reef.

Farming, grazing, mining, fishing, tourism, aquaculture and almost any kind of development are all paying a heavy price to prevent problems that can’t be shown to actually exist and for which there is no sound evidence of any measurable beneficial effect.

Unlike the imaginary threats, this is a real and present impact on the productive economy, and it is growing. One can only wonder who or what the eco-activists imagine will continue to support them if they succeed in their demands?

Sound policymaking demands the establishment of some mechanism to provide decision makers with well-informed critical assessment of the science on which they rely. The current approach of presenting advocacy only, bolstered by claims of authority and consensus with no mention of uncertainty or con­flicting evidence, is simply not good enough for decision-making or even to be valid science.

A Senate inquiry into ensuring evidence-based regulation of farming practices that impact water quality outcomes in the GBR is now being undertaken. Hopefully, the long overdue political recognition of the problem of misguided environmentalism is beginning to take effect.

Dr Walter Starck grew up on an island in the Florida Keys and in 1964 he completed a PhD at the Institute of Marine Science of the University of Miami. His research interest has centred on coral reef biology. He has extensive experience of reefs worldwide. In recent years he has written, spoken and consulted widely on environmental and resource-management issues.